One note about this addition.
The unregistered user who receives an offers for his post receives the message but does not know the sender's email and cannot reply because he does not have an account. Some setting should be done to be able to reply or not to show the offer button on the unregistered user's post.

Thanks for feedback, will look on it in next update.

Do we have any news about this problem?

As I have written, the unregistered user cannot respond to the offer made to him because he does not have the email. I think this problem can be solved if at least, along with the offer, the email address of the user sending the offer is displayed. Of course, the message that the unregistered user receives should be adjusted accordingly so as not to refer him to his account, which he does not have anyway.
Otherwise, this add-on is made only for registered users.

Solution is to send user to registration page.
Sharing email is not solution and this helps to engage user to register.

The email of course cannot be public, but visible only to the person who accepts the offer.
This solution you mention is a solution but not ideal.

Its only smart solution.